Condenser



Nov. 27, 1928. 1,693,173

1 G. H. BROWN v comasnssn' Filed 06111, 1925 Y 2 Sheets-Sheet I N VEN TOR.

Z5 A TTORNEY.

Nov. 27, 1928.

G. H. BROWN CONDENSER Filed Oct. 7, 1925 2 SheetsSheet 2 INVENTOR.

' 1 ATTORNE.

Patented Nov. 27, 1928. p I UNITED STATES PATENT OFFICE.

- GEORGE 3'. BROWN, 01' NEWTON, MASSACHUSETTS.

conpnnsnn.

This invention relates to electrical condensers and is especially concerned with condensers of the type used in radio telephony, and the like. I

It is an important object of the invention to simplify the operation of tuning in radio receiving apparatus and the invention provides a condenser which can be so adjusted in a receiving set that any one of a large number of'stations can be brought in fully tuned simpl by moving a lever or pointer to a designated position on a scale. It is contemplated, however, that the condenser will also be used in various other relationships.

It is a further object of the invention to devise an electrical condenser adapted especially for use in radio work which will be compact in construction, efiicient in operation, and economical to manufacture.

The nature of theinvention will be readily understood from the following description when read in connection with the accompanying drawings, and the novel features will be particularly pointed out in the appended claims.

Referring now to the drawings,

Figure 1 1s a perspectiveview of a portion of a radio receivin set including a con-t denser embodying this invention;

Fig. 2 is a vertical cross sectional view through the slide of the condenser shown in Fi 1; and

Fig. 3 is a plan view of a modified construction.

Referring first to Figs. 1 and 2, the condenser there shown comprises a main condenser clement 2 consisting of a block of metal having a series of grooves formed in its upper surface. Mounted in each groove is a condenser unit 3 consistin of a metal bar or plate. Each of these units 3 is electrically separated from the main condenser element 2 by thin mica sheets 4, or some other suitable dielectric material. The condenser units 3 are normally stationary, but each unit is adjustable backward or forward in its groove to vary or adjust its capacity, as may be desired. That is, the capacity of any .mit 3 will be decreased as it is moved end-,

wise out of its groove, so that its area opposed to the area of the main unit 4 is reduced. At one end the condenser element 2 is extended and provided with a binding screw 5 which provides for the convenient attachment of a conductor 6 to connect the element 2 with cooperating parts of the receiving set.

In order to connect any desired number of. the units 3 into the circuit, an electrical conductor 7 is provided which consists of a metal plate having a series of s ring fingers 8 integral therewith. The en s of these fingers overlie the units 3, and the plate 7 is elamped'to a metal base 9 which is provided with a binding post 10 so that a suitable connector or conductor, such as that indicated at 12, may be convenientl connected to it. Mounted between the base 9 and the condenser element 2 is a grooved bar 14 supporting a slide 15'which has a cam portion 16, best shown in Fig. 2, that separates high and low horizontal portions of the slide. The fingers 8 rest on the u per surface of this slide, and so long as the ow portion of the slide lies under the fingers they will all rest on the upper surfaces of the condenser units 3. As the slide is pushed to- Ward the left, however, the cam portion 16 thereof lifts the fingers progressively oil the units 3. Consequently, by making a suitable adjustment of the slide any desired number of the condenser units may be connected in the circuit, and the capacity necessary to modify an inductance to suit different wave lengths can, therefore, be readily obtained. This apparatus is especially useful in radio receiving sets of the neutrodyne or tuned radio frequency type where a plurality of 7 identical tuning units is employed. When so used it is convenient to attach a pointer 16 to the slide 15 and have this pointer project through a slot, such as that shown at 17, in the casing or cabinet 18which houses the set. A scale 19 preferably is so located that the pointer 16 moves over it and this scale can have the symbols of the different stations marked on it. In tuning the set initially for these stations the condenser units are adjusted independently of each other to the desired capacity necessary to bring in each individ' 'ual station clearly. After this initial adjustment has been made for a given series of stations, it is thereafter unnecessary to adjust the condenser units for those particular stations. In other words, in order to bring in any station it is simply necessary to move the slide 15 so that the pointer 16 will register with the symbol for thatstation, as for example, W. G. Y. The station then will come in fully tuned.

I c In order to get stations between those on the scale, and for convenience in fishing or searching for stations, the condenser preferably is equipped with a Vernier. This comprises a metal plate supported on a spring 21 and spaced from the end face of the metal block 2 by an air space which, in this case, forms the dielectric. An adjusting screw 22 bears against this plate and by turning this screw in or out the distance between this plate 20 and the part 2 may be varied, and the capacity of the vernier condenser consequently adjusted. A conductor 23 connects the Vernier 20 with the binding post 10.

Fig. 3 shows a slightly different arrangement in which the main condenser 2 and the adjustable condenser units 3 are constructed and arranged exactly as above described. In this construction, however, each of the condenser units 3 is connected by a conductor 24 to a contact post or button 25 embedded in a plate 26 of vulcanite or some similar insulating material, the surfaces of the contacts 25 preferably being lush with the surface of the insulating plate 26. A metal bar 27 carrying a series of spring fingers 28 is arranged to slide backward and forward over the plate 26 into engagement with the various contacts 25. By this arrangement any desired number of the condenser units 3 can be electrically connected into the circuit in much the same manner that they are connected into the circuit by the fingers 8 and slide 15 in the construction above described. The bar 27 slides through metal guides29-29 and a binding post 30 is connected to one of these guides to facilitate the connection of the condenser units into the receiving circuit. A Vernier similar to that shown in Fig. 1 can also be used in this construction.-

It will now be appreciated that this invention provides a condenser construction which is extremely simple, is very economical to manufacture, and has a high capacity'for a given size.

While I have herein shown and described the best embodiment of my invention that I have so far devised, it will be appreciated that the invention may be embodied in many forms without departing from the spirit or scope thereof. For example, the main condenser elements and the units cooperating therewith may be made in other forms, and the connections to the units may be made in a great variety of ways. Where size is not an important factor, the units may each be made to ave a capacity roughly suitable for different stations, and the initial tuning or adjustment for each station may be made by the adjustment of a condenser unit individual to that station, the switch member correspending to the parts 27 and 28 in Fig. 3 having but a single contact so that one condenser unit only will be working at a time instead of bringing the condensers in multiple, as shown. In the arrangement illustrated, particularly the form of the invention shown in Fig. 3, the adjustment of the capacity ofthe individual units can be made by swinging the bars 3 upwardly, or lifting them out of their grooves more or less, as well as by moving them endwise.

Having thus described my inventi n, what I desire to claim as new is:

1. A condenser for radio telephony and the like, comprising a series of variable condenser units, each adjustable independently of the of them into a circuit or to disconnect them from the circuit.

3. An electrical condenser comprising a main condenser element, a series of condenser units each cooperating with said element but electrically separated therefromby a dielectric material, said units being normally stationary.

with reference to said element but adjustable relatively thereto independentl of each other to vary the capacity of the in ividual units, and means for connecting any desired number of said units into a circuit.

4. An electrical condenser comprising a main condenser element, a series of condenser units each cooperating with said element but electrically separated therefrom by adielectric material, said units being normally stationary with reference to said element but adjustable relatively thereto independently of each other to vary the capacity of the individual units, an electric conductor located closely adjacent to said units, and adjustable means for electrically connectin any desired number of said units to said con uctor.

5. An electrical condenser comprising a main condenser element, a series of condenser units each cooperating with said element but electrically separated therefrom by a dielectric material, said units being normally stationary with reference to said element but adjustable relatively thereto independently of each other to vary the capacity of the individual units, an electric conductor located closely adjacent to said units, and a slidable device adjustable to electrically connect any desired number of said units to said conductor.

6. An electrical condenser comprising a main condenser element, a series of condenser units each cooperating with said element but electrically separated therefrom by a dielectrio material, said units being normally stationary with reference to said element but adjustable relatively thereto to vary the ca acity of the individual units, an electric con uctor having a series of fingers arranged to be conmain condenser element, a series of condenser units each cooperating with said element but electrically separated therefrom by a dielcctrio material, said units being normally sta tionarywith reference to said element but ada j ustable relatively thereto to vary the capacity of the individual units, a stationary electric conductor having a series of fingers arranged to be electrically connected, respectively, with said units, and a slidable cam operable to move said fingers progressively into and out of electrical connection with said units.

GEORGE H. BROWN.

CERTIFICATE OF CORRECTION;

Patent No. 1, 693,173.

GEORGE n. anoiva Granted November 27, 192 8, to

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction asfollows:

after the word -"thereto" Page 3, line 5, claim 6,

insert the words "independently of each other"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 29th day of January, A. D. 1929.

(Seal M. J. Moore, Acting Commissioner of Patents. 

